This invention is generally related to the detection, diagnosis, and analysis of impairment in a communication system, and more particularly to the use of probabilistic modeling of parameters in the system for detecting and diagnosing the impairment.
In the communications arena one of the biggest challenges is to overcome crosstalk, noise, and other disturbances that impair the signals. Whether the signals are transmitted over wires, cable, fiber optics wireless, or other types of communication, the signals suffer from some level of impairment. The impairment may be due to interference (such as electromagnetic interference from neighboring communication channels) and/or environmental factors (such as temperature and moisture due to rain and snow).
Impairment of the signal may lead to certain limitations of the communication system. For example in wire systems such as digital subscriber lines (DSL), the impairment may shorten the distance at which the signal can be reliably received, i.e., limit loop reach. A similar effect is encountered in wireless systems. Impairment may also decrease the bit rate of the data being transferred. Providers of telecommunications services recognize the need to monitor the quality of service provided to users of their networks and to identify the causes of impairments reported by their customers. This task, however, is complicated significantly by several factors.
Some of these factors include: the large number of network users, the large amount of data collected from the deployed lines, and the presence of competing providers in the same physical line plant. The coexistence of ILECs (incumbent Local Exchange Carriers) and CLECs (Competitive Local Exchange Carriers) in the same cable binders, brought about the federally mandated deregulation of local telecommunications markets, implies that services deployed by one carrier may be disturbing the users of another carrier, who has no information about the source of this disturbance.
It is thus highly desirable to sort through the collected data and determine whether a specific line is being disturbed by, for instance, external interference, such as AM radio stations, or by internal interference, such as another DSL service, and whether that offending service belongs to the same carrier or not. Unfortunately, with today's deployed monitoring technology, carriers are extremely limited in their ability to perform such diagnoses with adequate accuracy and reliability.